嵌套JSON序列化问题：SerializeJsonBody字段定义报错及解决尝试

问题背景 #

尝试序列化指定结构的JSON，已创建对应C#辅助类，但提示SerializeJsonBody无可用填充字段；深层类定义正常，却无法生成完整目标JSON。

目标JSON结构 #

{"invoiceHash": { "hashSHA":{"algorithm": "SHA-256","encoding": "Base64","value": "{0}"},"fileSize": "{1}"}, "invoicePayload":{"type": "plain","invoiceBody": "{2}"}}

对应C#类定义 #

public class SerializeJsonBody
{
    public invoiceHash invoiceHash { get; set; }
    public invoicePayload invoicePayload { get; set; }
}
public class invoiceHash
{
    public hashSHA hashSHA { get; set; }
    public string fileSize { get; set; }
}
public class hashSHA
{
    public string algorithm { get; set; }
    public string encoding { get; set; }
    public string value { get; set; }
}
public class invoicePayload
{
    public string type { get; set; }
    public string invoiceBody { get; set; }
}

错误赋值代码 #

SerializeJsonBody body = new SerializeJsonBody
{
    algorithm = "SHA-256",
    encoding = "Base64",
    value = "",
    fileSize = "",
    type = "plain",
    invoiceBody = ""
};

string json = JsonConvert.SerializeObject(body, Formatting.Indented);

问题根源 #

SerializeJsonBody本身并不包含algorithm、encoding等字段，这些属性属于它的嵌套子类（hashSHA、invoicePayload）。直接在SerializeJsonBody实例初始化时赋值这些字段，编译器会报错，且因未正确初始化嵌套对象，序列化后无法生成完整JSON结构。

修正后可行代码 #

SerializeJsonBody body = new SerializeJsonBody
{
    invoiceHash = new invoiceHash
    {
        hashSHA = new hashSHA
        {
            algorithm = "SHA-256",
            encoding = "Base64",
            value = base64hash
        },
        fileSize = lenght
    },
    invoicePayload = new invoicePayload
    {
        type = "plain",
        invoiceBody = base64
    }
};

string json = JsonConvert.SerializeObject(body, Formatting.Indented);

方案验证 #

你找到的修正方案是正确且最优的：通过嵌套初始化每个子对象，确保SerializeJsonBody的所有嵌套属性都被正确实例化并赋值，序列化后即可生成符合目标结构的完整JSON。

内容的提问来源于stack exchange，提问作者Tweene